With the increasing development of communication technologies, communication networks have presented the cross-coexistent situation of multi-patterns and multi-stages, such as the coexistence of Code Division Multiple Access (CDMA) network, Global System for Mobile Communications (GSM) network and Next Generation Network (NGN) and the like. A user may possess communication terminals corresponding to different networks so as to use different networks. In this case, it is generally desired by the user that the multiple terminals are represented with a same number, a main number, so that all the terminals bound to the main number can be connected when another user dials the main number. This type of service is one-number multiple-terminal service, the specific service types are specifically divided into the simultaneous ringing and ordinal ringing of all the bound terminals. Wherein, the one-number multiple-terminal simultaneous ringing service means that when a calling terminal calls the main number of the called terminals, all the terminals bound to the main number ring simultaneously; and the one-number multiple-terminal ordinal ringing service means that when a calling terminal calls the main number of the called terminals, all the terminals bound to the main number ring in sequence according to a predetermined order. The one-number multiple-terminal service greatly improves user experience and promotes the communication efficiency between users, and therefore has a bright market prospect.
Currently, both mobile phones and fixed phones including PHS (Personal Handy-phone System) are supported by all the domestic operators. As mobile phones are the most popular and convenient communication tool currently and the numbers of mobile phones are stored by most users, a mobile phone number is the first choice of the main number in the one-number multiple-terminal service.
Limited by the Wireless Intelligent Network (WIN) protocol of CDMA network and the Customized Application for Mobile Network Enhanced Logic (CAMEL) protocol of GSM network, it is difficult for the one-number multiple-terminal service to realize the simultaneous ringing or ordinal ringing of three or more numbers. With the development of NGN, NGN has converged circuit-switched networks, Public Switched Telephone Network (PSTN), Public Land Mobile Network (PLMN) and the like, and IP packet-switched networks, therefore, the problem above can be solved. However, how to realize the one-number multiple-terminal service, by using a mobile terminal number as a main number, becomes another problem in this field that should be urgently solved.